"The combination of performance, personality and purity, both of these guys have that," said Bob Dorfman, the executive creative director at the San Francisco advertising firm Baker Street Partners. "It's just kind of a question now of who can win the ring and have the staying power."

It is an uneven matchup going into the game, though.

The Patriots are favored on and off the field. They have a superstar quarterback with sex appeal who courts supermodels and actresses. Mr. Brady already has contracts with Nike, Movado and Glaceau Smart Water. He's even appeared in Gap ads.

Sports Illustrated estimates Mr. Brady pulled in $9 million in endorsements in 2007.

Mr. Manning, by contrast, is quiet, and engaged to his college sweetheart. He has appeared in commercials for ESPN and Oreos -- but primarily with his family. He has yet to hit the marketing spotlight on his own, lingering instead in the shadow of his brother, Indianapolis Colts quarterback Peyton Manning, and his father, former NFL quarterback Archie Manning.

"It's much bigger for Eli Manning than for Tom Brady," said David Carter, professor of sports business at the University of Southern California.

The Davie Brown index, created by Dallas-based Davie Brown Talent and used by marketers to measure the consumer influence of stars and athletes on consumers, shows a gap as well.

Overall, Mr. Brady is on par with celebrities such as actors Jude Law or Don Cheadle, with a score of 55.6. He scores high in terms of consumer appeal -- putting him in the ranks of actress Nicole Kidman or TV weatherman Al Roker.

Mr. Manning scores overall at 48 -- in the same neighborhood as comedian Stephen Colbert or Jon Heder, the star of Napoleon Dynamite . But he is highly ranked in the trust category, put in the same neighborhood as TV host Regis Philbin and actors Ben Stiller and Steve Carell.

To give some perspective, a top athlete endorser such as Tiger Woods would come in at 90 and Mr. Manning's marketing- friendly brother Peyton (who has a reported $13 million worth of endorsement deals) gets a score of nearly 62.

Sports marketing experts say this could be Eli Manning's breakout if he pulls off a Super Bowl win or establishes a style and panache of his own.

The potential endorsement line-ups would be different, experts say.

Mr. Brady has the sex appeal that makes him an easy pick for high-fashion or style-oriented products such as clothing or cologne. But experts say Mr. Manning has more appeal to younger crowds and everyman products, uncluding cell phones, video games and the like.

Experts say Mr. Manning could capitalize on his family's squeaky-clean image if the public doesn't have Manning fatigue. But clean-cut is a safe bet these days; no one wants another Michael Vick, the football player sentenced in December to 23 months in federal prison on dogfighting charges.

Mr. Manning might choose not to seek out the opportunities. When asked by The Associated Press what he would endorse if he could endorse anything, Mr. Manning replied: "I'm the spokesman for the New York Giants."

Mr. Brady, on the other hand, already has his choice of many deals and, given his regular appearances in celebrity news and tabloids, risks overexposure.

Experts say the sight of Mr. Brady hoisting a trophy amid the confetti and crowds could prove a powerful one that may sway Mr. Brady's endorsement decisions and not smack of overexposure.

Regardless of their choices, the Super Bowl will be a key day of exposure for both players.

"It's pretty significant because there are 90 million people watching and it's a lot of non-football fans," Mr. Dorford said. "It's a lot of people who wouldn't normally watch these guys."